What is an "All-Day Singing"?

Folks gather at the selected site, early enough to fill out
a registration card and greet old friends before the start
time, which is often 9:30 am thus folks begin to gather at
about 9:00 am, then seat themselves in one of four sections:
tenor (which is the melody part sung by both men and women),
treble (a high harmony part sung by both men and women),
alto, or bass. Sacred Harp is sung with a "hollow square"
arrangement in which these parts all face the middle. (see
picture)

A chairman, or two co-chairs, will welcome everyone, and
after the chaplain for the day has led everyone in an
opening prayer, the singing commences! Everyone has their
own copy of either The Sacred Harp (1991 Denson
edition) or The Sacred Harp (2012 Cooper Revision)
or a loaner copy picked up at the registration table near
the door. Each all-day singing will have chosen in advance
which book they use.

Once the day gets going, a singer will enter the square,
call out a page number, and lead the class in singing the
song on that page.

Leading is egalitarian at Sacred Harp singings, that
is, each song is led by a different person, standing in
the center of the hollow square. Newcomers are welcome to
try their hand at leading, just face the tenor section and
follow the hand motions of the front row.

Someone will have been delegated to call out names of
those who have indicated that they would like to lead a
song, and these leaders are called to the floor one after
another.

A ten minute break is taken every hour for refreshments
(keeping hydrated is important at all-day singings!) and an
hour-long break is taken at noon for Dinner, which is a
potluck meal called "Dinner-on-the-Ground". The singing
usually comes to an end about 2:30 or 3:00 p.m.

So "All-Day" really means from about 9:30 to 2:30 or 3:00
thus about 4 1/2 hours of vigorous singing. By the end of
the singing, upwards of 90 songs will have been sung.